Gaseous fuel carburetor



I5 Sheets-Sheet l INVENTOR.

JACK R. PHIPPS J. R. PHIPPS GASEOUS FUEL CARBUREIOE Feb. 10, 1970 FiledJan. 23, 1967 FIG.

Feb; 10, 1970 J. R. PHIPPS GASEOUS FUEL .CARBURETOR 3 Sheets-Sheet 2Filed Jan. 23, 1967 FIG. 4

United States Patent 3,494,750 GASEOUS FUEL CARBURETOR Jack R. Phipps,St. Clair Shores, Mich., assignor to The Bendix Corporation, acorporation of Delaware Filed Jan. 23, 1967, Ser. No. 610,854 Int. Cl.B01f 3/02 US. Cl. 48-184 11 Claims ABSTRACT OF THE DISCLOSURE A gaseousfuel carburetor having a port at the venturi for sensing flowtherethrough in combination with a fuel discharge port spaced along theinduction passage from the venturi port.

The present invention relates to carburetors and more particularly to acarburetor for liquefied petroleum gas for internal combustion engines.

In the conventional carburetor for liquefied petroleum gas for internalcombustion engines, the supply of gas is regulated by a series ofdiaphragms responsive to pressures at various points in the carburetorinduction passage, particularly at the venturi, and the gas is meteredand normally discharged into the throat of the venturi. Since one of theprincipal pressures employed in regulating the flow of gas is theventuri, the discharge of gas into the venturi tends to disruptperformance of the regulator and metering system and has resulted in atendency for the fuel in the fuel-air ratio to become less at a timewhen an increase in the fuel is normally required. While the foregoingadverse condition has long been recognized in the industry, theadvantages of discharging the gas into the air at the venturi to obtaineffective distribution of the gas in the air flow have outweighed thedisadvantages of poor or improper control of the regulator, since thesedifiiculties or deficiencies can be and have been compensated for byadditional means in the carburetor to provide the correct fuel-air ratiounder all normal operating conditions. These additional means, however,have rendered the carburetor rather complicated and difiicult to adjustand service, and have often resulted in erratic and unreliableperformance and poor response to variations in engine operatingconditions. It is, therefore, one of the principal objects of thepresent invention to provide a carburetor for gaseous fuel whichutilizes the pressure in the venturi as one of its primary controlpressures for the regulation, and which is so constructed and arrangedthat the discharge of fuel into the induction passage does not adverselyaffect venturi pressure sensed by the regulator.

Another object of the invention is to provide a carburetor for gaseousfuel, which senses the pressure of the venturi but which discharges thefuel into the air stream anterior thereto, thus permitting the venturito respond to the flow of the fuel-air mixture rather than merely theair flow, and thereby obtaining optimum performance with a minimumnumber of systems and metering correction features.

A further object of the invention is to provide a carburetor for gaseousfuel of the aforesaid type which accurately regulates and meters thefuel in response to venturi pressure, and which provides effectivedistribution of the fuel in the air flowing through the carburetor.

Additional objects and advantages of the invention will become apparentfrom the following description and accompanying drawings, wherein:

FIGURE 1 is a top plan view of the present carburetor;

FIGURE 2 is a vertical cross-sectional view of the carburetor, thesection being taken on line 22 of FIG- URE 1;

FIGURE 3 is in effect a vertical cross-sectional view taken on line 3-3of FIGURE 2, actually being an elevational view with a portion of theregulator removed from the body of the carburetor;

FIGURE 4 is a horizontal cross-sectional view of the carburetor, thesection being taken on line 4-4 of FIG- URE 3;

FIGURE 5 is a vertical cross-sectional view taken on line 55 of FIGURE1;

FIGURE 6 is an enlarged fragmentary vertical crosssectional view of thecarburetor taken on line 66 of FIGURE 1;

FIGURE 7 is an enlarged fragmentary cross-sectional view taken on line77 of FIGURE 2, and;

FIGURE 8 is an enlarged fragmentary vertical crosssectional view takenon line 88 of FIGURE 1.

Referring more specifically to the drawings, and to FIGURES 1 and 2 inparticular, numeral 10 designates the body of the carburetor having aninlet passage or air horn 12, venturi 14 and throttle body 16, havingmounted therein throttle 18 on shaft 20 journaled in the side wall ofthe throttle body. A flange 22 is formed integrally with the throttlebody and is provided with holes 24 and 26 for receiving screws forsecuring the carburetor to the inlet of the intake manifold of aninternal combustion engine (not shown). The air horn contains a chokevalve 28 mounted on a shaft 30 which, in turn, is journaled in thesidewall of the air horn, the air horn normally being provided with anair filter secured to the external wall thereof. The carburetor thus fardescribed may, for the purpose of the present description, be consideredconventional in construction.

A fuel regulator is mounted on the side of the carburetor body and issecured thereto by a plurality of screws 42 extending through theregulator into the body structure. The regulator consists of threeprincipal sections 44, 46 and 48 containing chambers 50, 52 and 54,respectively. Chambers 50 and 52 are separated by a flexible diaphragm56 and chambers 52 and 54 are separated by a diaphragm 58, thediaphragms being clamped in sealing relationship between the walls ofthe respective sections, and held securely in place by screws 59,Chamber 50 is connected to the fuel inlet passage 60 which, in turn, isconnected to a source of fuel, such as a cylinder wherein the gaseouspetroleum is maintained under suflicient pressure to liquefy the gas. Apressure regulator and vaporizer (not shown) are normally in the linebetween the source and inlet passage. The fuel is delivered to fuelinlet '60 in a gaseous form and is controlled by an inlet valve 62consisting of element 64 joined to an arm 66 which is pivoted to movevalve element 64 to and from its seat 70 on the upper end of inletpassage 60. The valve 62 and arm 66 are pivoted on a leaf spring member72 secured to the wall of section 44 by screws 74. Lever 66 is urged inthe direction to seat valve element 64 onto seat 70 by a coil springreacting between the side of the carburetor body and the upper end ofthe lever.

The valve is controlled by pressures in the carburetor transmitted tochambers 52 and 54 and acting on diaphragms 56 and 58, diaphragm 56having a center lug 82 for contacting a projection 84 on lever 66.Diaphragm 58 is operatively connected to the lever by a member 86attached to the diaphragm 56 and engaging the reinforcing member 88 ofdiaphragm 58, the reinforcing member being secured to the latterdiaphragm by a rivet construction 90. Chamber 52 is connected to thethroat of venturi 14 by a passage 92 in sections 46, 44 and thecarburetor body 10, and port 94 in the venturi, and hence diaphragms 56and 58 are subjected to and principally controlled by the variations insuction in the venturi. Chamber 54 is connected to inlet passage 12 inthe air horn by port 100,

passage 102 and port 104 in the carburetor body and in sections 46 and48, a restriction 106 preferably being provided in passage 102. It isthus seen that diaphragm 56.is partially controlled by inlet pressure,which Will remain substantially constant throughout most of theoperation of the engine. However, variations in pressure will occur inthe event the air cleaner becomes partially clogged with foreign matter,and to a slight extent from impact pressure from the effect of air flowon port 100.

Gaseous fuel on leaving inlet passage 60 passes into chamber 50 andthence through passage 110 to metering valve 112 and discharge jet 114,the valve 112 :being adjusted by screw 116 threadedly received invalveboss 118. The position of jet 114 is in substantially directalignment with the center of the venturi and discharges the fuel intothe air as it leaves the air horn and is approaching the entrance to theventuri. As can be seen in the drawings, the jet 114 is located asignificant distance longitudinally along the induction passage from thepressure sensing port Q4. At this point the air flow is relativelyturbulent and hence the gaseous fuel is readily dispersed, distributedand mixed in the air to form an effective combustible. mixture. Thefuel-air mixture thus formed passes through the venturi where the flowthereof is sensed through port 94 and passage 92 by diaphragms 58 and56. As the flow through the venturi is increased and the pressure at thethroat thus decreases, diaphragm 58 moves to the left as viewed inFIGURE 2, urging lever 66 to the left, thereby further opening valve 64and admitting a greater quantity of fuel to mix with the greaterquantity of air passing through the carburetor to the engine. Themovement of diaphragm 58 and lever 66 to the left is opposed by spring80 which returns the diaphragm and lever to their original position asthe air flow in the venturi decreases.

The present fuel system may include a back suction economizer, such asthat illustrated in FIGURE 8, in which a port 120 is in the inductionpassage adjacent the throttle valve on the air intake side thereof, whenthe valve is connected to chamber 54 by passages 122 and 102. When thethrottle is opened for acceleration, the adjacent edge of the throttlepasses port 120, permitting the port to communicate with the engine sideof the throttle, and hence transmit manifold vacuum through passage 122and to chamber 54. Passage .122 is connected to passage 102, which inturn is connected to chamber 54; thus, as the throttle is opened andmanifold vacuum transmitted through port 120 and through passages 122and 102 to chamber 54, diaphragm 58 moves to the right, as viewed inFIGURE 2, permitting spring 80 to move valve 64 further toward closedposition and thus reducing the amount of fuel delivered to the engine.As the throttle valve is moved to substantially wide open positionduring acceleration, the drop in pressure in the manifold is relativelysmall and the vacuum transmitted to chamber 54 has little effect ondecreasing the amount of fuel which otherwise would be delivered to theengine.

The idle system is connected to chamber 50 and consists of a passage130, a discharge jet 131, and an idle valve 132, the idle valve beingadjustable toward and away from jet 131 by thumbscrew 134 threadedlyreceived in boss 136 and held in adjusted position by spring 138. An airbleed 140 is provided on the air intake side of throttle valve 18 whichassists in forming an efl ective fuel-air mixture discharged through jet131. When the engine is idling, air. is drawn into chamber 50 throughorifice 142 and orifice 114 and mixes with the gaseous fuel in chamber50. This rich fuel mixture flows through passage 130 where it mixes withadditional air from port 140 and is then discharged through jet 131. Asthe throttle is opened, it passes port 140, thus rendering the portineffective as a supply of air for the idle system and permitting theamount of fuel discharged through the idle system to be increased tocompensate for the increased air flow until the main jet 114 and orifice142 become operable to supply the required fuel.

In the operation of the foregoing carburetor starting with the throttlevalve in closed position and the engine running, fuel is supplied to thecarburetor through the idle system with air flowing through chamber 50through orifices 142 and 114 into chamber 50 and thence through the idlesystem to discharge jet 131. Manifold vacuum transmitted through passageto chamber 50 causes diaphragm 56 to open valve 64 sufliciently tosupply the fuel needed for idling. When the throttle valve is opened,the air flow through the venturi creates a vacuum therein which istransmitted to chamber 52 where it, acting upon diaphragms 56, and 58,moves lever 66 to the left as viewed in FIGURE 2, thereby furtheropening metering valve 64. The diaphragm 58 being substantially largerin area than diaphragm 56, causes the two diaphragms to move to the leftwhen the pressure therebetween is decreased sufliciently to overcome thefuel pressure in chamber 50. The vacuum from the venturi is balancedagainst the fuel pressure in chamber 50 and against air inlet pressuretransmitted to chamber 54, permitting the carburetor to regulate theflow of fuel to obtain the proper fuel-air ratio, irrespective ofvariations in inlet pressure of the fuel or inlet pressure of the air,and thus maintaining the proper fuel ratio under all variations inoperating conditions. As the throttle valve is opened beyond port 120,the richness of the fuel-air mixture is decreased by the back suctioneffect created in chamber 54, thus obtaining a somewhat leaner mixtureduring normal operation of the engine. When the throttle valve is movedto substantially wide open position, the effect of the back suction ondiaphragm 58 becomes insignificant and a relatively rich mixture ishence supplied to the engine for high power output.

While only one embodiment of the present invention has been described indetail herein, various changes and modifications may be made to suitrequirements.

I claim:

1. A carburetor for gaseous fuel, comprising a body having an inductionpassage with an air inlet and a fuelair mixture outlet, a throttle insaid passage, a venturi in said passage anterior to said throttle, afuel inletmeans, a fuel discharge port in said induction passageanterior to said venturi, a fuel passage connecting said fuel inletmeans with said discharge port, a valve in said fuel passage, pressuresensing means at said venturi for sensing venturi suction created by theflow of fuel-air mixture through said venturi, and a regulating meansoperatively associated with said pressure sensing means for controllingsaid valve substantially according to said venturi suction, whereby thelocation of said discharge port prevents the discharge of fuel fromadversely affecting the sensing of flow-created suction by said pressuresensing means.

-2. A carburetor as defined in claim 1 in which the carburetor has aninduction passage with a horizontal inlet portion and a vertical portioncontaining the venturi, and in which said fuel discharge port ispositioned in substantially axial alignment with said venturi.

3. A carburetor as defined in claim 1 in which an idle system conduitconnects said fuel passage with the induction passage on the posteriorside of the throttle.

4. A carburetor as defined in claim 1 in which said pressure sensingmeans includes a port in said venturi and said regulating means includesa housing having in series a gaseous fuel chamber connected to said fuelinlet means, a chamber connected to said pressure sensing port in saidventuri, and a chamber connected to the induction passage inlet, anddiaphragms separating said chambers and being operatively connected tosaid valve, the diaphragm separating said venturi pressure chamber andsaid air inlet chamber being larger in area than the diaphragmseparating said fuel chamber from said venturi pressure chamber.

5. A carburetor as defined in claim 4 in which the carburetor has aninduction passage with a horizontal inlet portion and a vertical portioncontaining the venturi,

and in which said fuel discharge port is positioned in substantiallyaxial alignment with said venturi.

6. A carburetor as defined in claim 5 in which an idle system conduitconnects said fuel passage with the induction passage on the posteriorside of the throttle valve.

7. A carburetor as defined in claim 6 in which the chamber in saidhousing subjected to air inlet pressure includes a passage connected tothe induction passage anterior and adjacent to said throttle valve in aposition to create a back suction condition in said air inlet pressurechamber when said throttle valve is partly opened.

8. A carburetor as defined in claim 4 in which the chamber in saidhousing subjected to air inlet pressure includes a passage connected tothe induction passage anterior and adjacent to said throttle valve in aposition to create a back suction condition in said air inlet pressurechamber When said throttle valve is partly opened.

9. A carburetor as defined in claim 4 in Which said valve includes anoperating lever and a spring urging said lever in the direction to closesaid valve in opposition to the pressure on said diaphragms.

10. A carburetor as defined in claim 9 in which said valve and lever arepivoted on a leaf spring.

11. A carburetor for gaseous fuel, comprising a body having an inductionpassage with an air inlet and a fuelair mixture outlet, 21 throttle insaid passage, a venturi in said passage anterior to said throttle,pressure sensing means at said venturi for sensing flow through saidventuri, a fuel inlet means, a fuel discharge port in said inductionpassage anterior to and spaced a predetermined distance longitudinallyalong said induction passage from said pressure sensing means to preventthe discharge of said gaseous fuel from adversely affecting flow sensingby said pressure sensing means, a fuel passage connecting said fuelinlet means with said discharge port, valve means in said fuel passagefor controlling the flow of fuel therethrough, and a regulating meansoperatively associated with said pressure sensing means for controllingsaid valve substantially according to said flow through said venturi.

References Cited UNITED STATES PATENTS 1,436,690 11/1922 Secor 481802,209,206 7/ 1940 Peduzzi 481 4 2,346,763 4/1944 Jones 48-180 3,009,79411/1961 Barfod 48184 3,068,085 12/1962 Ensign et al. 48-184 JOSEPHSCOVRONEK, Primary Examiner US. Cl. X.R.

